The present invention relates generally to headphones and earphones featuring ambient noise cancellation (“ANC”)—sometimes termed ambient noise reduction (“ANR”)—commonly used at present in conjunction with mobile electronic devices such as cellular telephone handsets and music players. In particular, the invention relates to physical arrangements that are integrated into the headphones and earphones and which allow the noise-cancellation processing to be calibrated without the use of external measurement systems, in order to allow very rapid manufacture with minimal manual involvement on the production-line. The present invention is particularly suitable for feedforward-type ANC headphones and earphones.
For simplicity of explanation, the invention will be described in respect of an ANC headphone. It will be appreciated that the invention is equally applicable to an earphone, including those in headsets for communication.